In geographic regions, which receive substantial snowfall, the hazards of falling snow or ice pose problems, particularly, for buildings or structures having a sloped metal roof surface or decking. These problems tend to be significantly exacerbated where the pitch of the roof decking is severe. The problems are caused, in part, by the fact that there is typically little friction between the roof decking and the snow to counteract the action of gravity and inhibit the snow from sliding off the roof decking. Moreover, ice sheets often form on the roof decking because the roof decking, being made of metal, tends to absorb heat from the structure or building. This heat melts the snow accumulated on the roof decking and forms ice sheets that can then slide off the roof decking potentially injuring people on the ground or causing damage to property.
Attempts have been made to control or restrain the sliding movement of snow or ice on sloped roof surfaces by installing snow guard devices on the roof decking. Conventional snow guard devices often include a pair of brackets with mounting blocks secured directly to the roof decking or to an underlying roof substructure, and a plurality of straight rods extending between the pair of brackets, which serve to block the sliding movement of snow. However, this type of snow guard is not particularly well-suited for corrugated roof surfaces or roof surfaces of the type having standing seams as it tends to require that the mounting blocks be mounted between each pair of adjacent corrugations or adjacent standing seams (as the case may be), with each mounting block requiring individual attachment to the roof decking or roof substructure.
In the case of corrugated roof decking, each of the brackets or mounting brackets may be secured to ridges of the corrugations by fasteners. This installation may be time consuming and may require puncturing the roof decking to form holes to accommodate the bolts or screws used to secure the snow guard device onto the roof decking. The large number of punctures thus created tends to compromise the imperviousness of the roof decking.
In the case of roof decking with a standing seam, various ways of attaching the brackets to the roof decking have been devised.
Typically, the manner of attachment involves securing the brackets or mounting blocks to the standing seams either with screws or bolts. However, this too can result in tearing or puncturing of the standing seams, which could compromise the watertight seal between adjoining roof panels. Alternatively, clamping mechanisms, which frictionally engage the standing seam to hold the snow guard device in place, have been used. However, these types of mechanisms tend to be susceptible to separating from the standing seam when the force exerted by the snow load exceeds the friction force between the contact surface of the clamp mechanism and the standing seam. This creates further hazards as the snow guard device could itself become detached from the roof decking and fall off the sloped roof.
Accordingly, it would be desirable to have a snow guard device which would tend to minimize the number of punctures created in the roof decking and which could be secured to the roof decking in a safe, stable manner.
It would further be advantageous to have a versatile snow guard device, which could be used, on different types of sloped roof surfaces, particularly those having standing seams and corrugations.